What does localized or lateralized high voltage delta indicate?

Localized or lateralized high voltage delta waves on an EEG typically indicate a focal process affecting the brain. These high voltage slow waves, particularly delta waves, suggest dysfunction in a specific area of the cortex. A cerebral abscess is a localized infection that can lead to increased intracranial pressure and tissue damage, often presenting with localized high voltage delta on EEG. This is due to the inflammatory process and the presence of necrotic tissue, which can disrupt normal electrical activity in that region.

While other conditions like subdural hematoma, encephalitis, and brain tumors can also cause abnormalities in EEG readings, they may not specifically lead to the same distinct pattern of localized high voltage delta waves. For instance, subdural hematomas may produce more diffuse changes or focal spikes depending on the extent of the bleeding, whereas encephalitis typically presents with more generalized slowing. Brain tumors can exhibit various EEG patterns depending on their type and location, including focal spikes or slow wave activity, but localized high voltage delta is more characteristic of an acute focal insult like a cerebral abscess.